Deflection coil assembly

ABSTRACT

Deflection coil pair for the color camera wound from insulated metal foil to a rectangular or trapezoidal block, which after baking is bored at right angles to the winding axis and machined to the desired tubular or hollow conical shape.

United States Patent Tan et al. [4 1 May 30, 1972 54] DEFLECTION COIL ASSEMBLY [56] References Cited [72] Inventors: Sing Llong Tan; Mathijs Willem Bartels; UNITED STATES PATENTS Walter Wilhelmus Johannus Degger, all of Emmasingel, Eindhoven, Netherlands 3,225,269 l2/ I965 Worcester ..336/206 X 2,949,593 8/1960 Staley et al. ....336/206 X [73] Assignee. U.S, Philips Corporation, New York, NY. 2'207777 7/1940 main 313/76 x [22] Filed: Sept. 25, 1970 2,167,379 7/1939 Tolson.... ..3l3/76 [21] Appl' 75372 Primary Examiner-George Harris ArmrneyFrank R. Trifari 30] Foreign Application Priority Data Oct. 3, i969 Netherlands ..69l5054 [57] ABSTRACT Deflection coil pair for the color camera wound from insu- [52] US. Cl ..29/605, 335/2l3 lated metal foil to a rectangular or trapezoidal block, which Int. Clafter is bored at angles to the axis and Field of Search 1 machined to the desired tubular or hollow conical shape.

4 Claims, 4 Drawing Figures PATENTEU MAY 3 0 m2 INVIzN'l'URS SING LIONG TAN MATHUS W. BARTELS WOLTER W.J. DEGGER m' x K C, WM

AGENT J DEFLECTION con. ASSEMBLY This invention relates to a deflection coil assembly particularly for use with a color television camera tube comprising two coils forming together a hollow cylinder or cone.

Deflection coils for use in color television, particularly with the camera, in which a separate cathode-ray tube is employed for each of the three fundamental colors, have to meet severe requirements with respect to the relative equality of the deflection coils to be used in one apparatus, for example, for horizontal deflection, in order to avoid display errors. It is known to build up a flat deflection coil from a plurality of nesting rectangular coil portions of progressing size and to bend the coil assembly, baked together in the form of a fairly rigid unit, into the required semi-cylindrical shape. In practice, it is not possible to wind coil portions of normal wire with absolute regularity and, moreover, during the bending operation the coils, having only slight resistance to deformation, are subjected to secondary deformations so that in this way accurately identical coil pairs cannot be obtained.

An object of the invention is to provide a structure which does permit of doing so, while it is not necessary to bend the coils into the desired shape subsequent to winding.

Thedeflection coil according to the invention is characterized in that the coil assembly is formed from a block of substantially rectangular or trapezoidal windings of a metal foil provided on at least one side with an insulating layer, said block being shaped by machining into the form of a hollow cylinder or cone, the axis of which is parallel to the longer axis of symmetry of said rectangular windings or to the axis of symmetry of the trapezoidal windings.

It is known to wind coils for electro-magnets pairwise from metal foil. However, we are concerned here with coils whose shape is no longer changed after winding.

The invention will be described more fully with reference to the drawing, in which:

FIG. I shows one embodiment and the method of manufacturing the same in a perspective view,

FIGS. 2 and 3 show the same embodiment and a variant thereof in an axial view and a side view, respectively, and

FIG. 4 shows a second embodiment in a side elevation.

FIG. 1 shows a deflection coil assembly 1 made from a block 3 of wound copper foil of, for example, O.l mm thick and, for example, cms wide, said foil preferably being coated on one side or on both sides with thermoplastic insulating lacquer. The foil is wound around a core 5, for example, of wood and, for example, of rectangular section and after winding it is baked in known manner into a solid block which can be machined by chipping tools such as a drilling machine or a lathe. As will be apparent from FIG. 1 (see also FIG. 2), the deflection coil assembly 1 comprises two coils forming together a hollowcylinder, the axis of which is parallel to the longer axis of symmetry 4 of the mainly rectangular windings of the block 3. The deflection coil assembly may be manufactured by boring the initial block 3 in said axial direction, after which the bored block can be fixed to a rotatable mandrel and the block portions shown in FIG. 1 on the left-hand and righthand sides can be sawed off. Subsequently both the outer and inner surfaces of the cylinder may, if desired, be refined on a lathe. Owing to these chipping operations the edges of the foil turns will, in general, be welded together at many places and thus be short-circuited. These short-circuits can be removed by etching the coil in known manner.

Without particular measures the coils of the deflection coil assembly 1 of FIG. 1 are connected to each other at one end so that these coils have to be connected in parallel with each other. lfthe two coils also have to be connected in series, two axial saw cuts 7 can be made in the block 3 (in FIG. 2 shown in broken lines) prior to machining thereof, which cuts separate the coils electrically from each other. The sawcuts 7 are then filled out with synthetic resin and the block is further machined in the manner described above.

FIG. 4 shows a variant in which the metal foil is wound on a trapezoidal-section core, the resultant block thus havin trapezoidal turns. From the block obtained a deflection cor assembly in the form of a hollow truncated cone can be obtained, the axis of which is parallel to the here unique axis of symmetry9 of the trapezoidal turns of said block.

The cross section of the winding mandrel and the inner shape of the bore may deviate slightly, without any objection, from the purely trapezoidal or conical shape, if it is desired for matching the shape of the cathode-ray tubeto be employed, the outer side of which may have a flaring shape. Reaming of such a shape on the lathe does not give rise to difficulties.

What is claimed is:

l. A method of fabricating a coil assembly composed of two electrically separated coils from a conductive strip of metal foil having a layer of insulating material on one surface thereof which comprises, spirally winding said foil strip about a core shaped so as to form a tubular coil body which, in cross-section, comprises four sides, two opposed sides of which are parallel and the other two opposed sides of which are substantially equal in length and longer than the two parallel sides, baking said coil body, cutting two parallel opposed grooves in the outer surface of the coil body along an axis orthogonal to the long axis of the tubular coil body and parallel to the longitudinal axis of symmetry of the four sided figure in cross-section, machining said coil body so as to form another tubular body of generally cylindrical or conical configuration with its major axis parallel to said longitudinal axis of symmetry, and filling said grooves with a synthetic resin material.

2. The method of claim 1 wherein said machining step includes the step of boring an aperture in said coil body parallel to said longitudinal axis of symmetry.

3. The method of claim 1 wherein said core has a rectangular cross-section thereby to form an apertured coil body with a rectangular cross-section having said longitudinal axis of symmetry, said machining step thereby deriving a coil assembly comprising two coils each having rectangular windings.

4. The method of claim 1 wherein said core has a trapezoidal cross-section thereby to form an apertured coil body with a trapezoidal cross-section having said longitudinal axis of symmetry, said machining step thereby deriving a coil assembly comprising two coils each having trapezoidal windings.

I i i i 

1. A method of fabricating a coil assembly composed of two electrically separated coils from a conductive strip of metal foil having a layer of insulating material on one surface thereof which comprises, spirally winding said foil strip about a core shaped so as to form a tubular coil body which, in cross-section, comprises four sides, two opposed sides of which are parallel and the other two opposed sides of which are substantially equal in length and longer than the two parallel sides, baking said coil body, cutting two parallel opposed grooves in the outer surface of the coil body along an axis orthogonal to the long axis of the tubular coil body and parallel to the longitudinal axis of symmetry of the four sided figure in cross-section, machining said coil body so as to form another tubular body of generally cylindrical or conical configuration with its major axis parallel to said longitudinal axis of symmetry, and filling said grooves with a synthetic resin material.
 2. The method of claim 1 wherein said machining step includes the step of boring an aperture in said coil body parallel to said longitudinal axis of symmetry.
 3. The method of claim 1 wherein said core has a rectangular cross-section thereby to form an apertured coil body with a rectangular cross-section having said longitudinal axis of symmetry, said machining step thereby deriving a coil assembly comprising two coils each having rectangular windings.
 4. The method of claim 1 wherein said core has a trapezoidal cross-section thereby to form an apertured coil body with a trapezoidal cross-section having said longitudinal axis of symmetry, said machining step thereby deriving a coil assembly comprising two coils each having trapezoidal windings. 